SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3891677308255fe326f5d9823dbe8a97816cfaf7ff50de1731674189502b4602' 
  AND token = 'bHnj+q16LqgEcJfcjQ9nwySmjWAgcxUBQ7KByLKetfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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