SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbc94db57d27ff1160f72672c245a4caaff9eead365fe3723c28e74a4c6d7306' 
  AND token = '+Mg0hMYsuk14m1JWDMqCnHXBuzb/mNgGX/766xGIO/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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