SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5bf51536551be549b1f406721c256dff4711cf9d20c46e17026dca8fcf59da6' 
  AND token = 'ebVK6TyUKKeox/TqtvHPJGHoJwWf2/QzZpFYEhH3H0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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