SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71c72ee96d9893626fb57237c216c519e0eeb0257589e11c4800146f2f82a81e' 
  AND token = 'u0Vs3OfB7xVY6BjGbZq5+NX/V+tRFr0ZQq0XHMmlSFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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