SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b710cb45010ea90716ffc884ef3b33b8924c897ea3bd4c8d37ed4d389c1a3a5' 
  AND token = 'gwxcvf2ypyUqxxfj+GEGP+5yQ5qnHIPf8rdM0whp9LY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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