SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f03e68748d40fd5fe74f877387713a94add0614d52390df85bb3994847582c' 
  AND token = 'f9oVcoeljYWdwaaN0Apk2EKF33WHLITiaC6lTYbuILE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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