SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c6268c17590bbe82ab45818512bfea512538a21a4e160cab4e2d39682d17409' 
  AND token = 'ouehc196/JCL0hmECq86lXdvoYgT12073n0FBcYsUlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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