SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '054e211773cbc9b5c73d788c5f51586458c6a29f2347259b5de72b1baebba524' 
  AND token = 'nfVpICNGB7N5EYK1ujZ6QF5PKRATwDYOo5Qb+L74exA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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