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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9c4f47abb49464bb7a6d46bb81319aea84727bf17631583f5b5af567412a0c8' 
  AND token = 'En4kb0PKAqTsHRW0fMsN5NHO8175g2Kp7vQ91ApNy30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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