SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7570795fa61c44def175b004cd43566d785bc7376c537a56e46287a1cc1cb1dc' 
  AND token = 'vtJ9/ch9CEv3qFRmaekPdN8+2h3zGJdPXwAAj9KMZzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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