SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd48c3ecea247fe636cf5bcd85eee89179988602c5b3e656c325ed752f9ee008c' 
  AND token = 'W8atKJhGCZkQR9v7p6NRjJsj4J7NV+jABkvFdGHi7uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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