SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee5b17467d8c8cfe89551cf9e7c026af1169a68e846e93bf8933106f51884dc9' 
  AND token = 'hePmGuulSR+s5clq/c92BolYXiw8jslI7Rxi4hMEJzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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