SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d8897a04202c55f8c754760c1c355a2d61a807b118fbf6d64dabe6f2d3581b9' 
  AND token = 'pPPC67YH5rEEGZ9qHF+fQLDVrKlkjEYwB3/FctNrsXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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