SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '51c96ba7638f28d94fbeb5c46220128a8408ded2445a93ffaeb01b0165437d75' 
  AND token = 'j9hMI13DwsrpqYGPREXQ/nU26fEj6P8g30Gis1wxwEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}