SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eace55012b6c2e89ffe1b7c44d09171cfd7c6fd5207b56dbebc80399487f1968' 
  AND token = 'CVyOFrnCU6eiXpV/SKJBKgR9ThxS1L8ZZ3vCQsVGa84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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