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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '831b679ddf039d8868e198aa2c97575b0cee7974d0851e0b318bcbfc25550c33' 
  AND token = '02edW5YVjQoQMl1uqaEHdwGIG8+mqhBKZagXsPN1XRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00007

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}