SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38de92c31763760acb236862caa8ef989087a65f7cffa1c2852a70971ce8d5f5' 
  AND token = 'G5BjcL8AVdRzoHNG5phhsKNzZPjwhokvq523yegfb4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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