SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6740840eec1afa02fa78b9542b34d959f600a64220fa1bc0d6426dc70fd315' 
  AND token = 'e6Jswp80fCAjVZnWkqfKxruCzerNLe6d5kxlVrwcec0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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