SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36e493fc153e3337ae895a875be2969983740ad78337f7ad73dbce7a05c1431b' 
  AND token = 'a6Wbsvs9Kyqa615HpqiwqQKXsl7jd5xmWK4cDPBpBgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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