SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88585678b38602f3044797a2a975e33258ad0075eac40a53a32dd92bbc35576d' 
  AND token = 'C4COfM2rvylC0rCvWSCGW8JozRl9PtAqr7nbc9Mf4ps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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