SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '223269004bc0d97b373d79d11adb290dc8a8bf678370af8f3504af196e61a277' 
  AND token = 'mhZ14q1R41Riyx1XDZ3EmfwLjHtMZVPILVYgDALRk7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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