SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5ebedc6824594767c3eb42e1a5b8739fd876d321309430ac2f169e161b6ad5c' 
  AND token = 'EFXM+fIz3YB86meA1jkGBNoUGLcGrtb0L/xDtCOHJ2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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