SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cf89dfd269ccf1ec2feec47f25cfe10bae955eb952267b1901339947a877522' 
  AND token = 'PF4N4fZElqBjgKvIcmql4ei3iKoIqqce03Cuec6SkaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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