SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '537b9318e36ce3a7fecaa512d2bcd99da45376e2f947ee5c5cc6b7cb76c97543' 
  AND token = 'Q6MC86nKiUK2arW4wjf3/uyhKJKLwH5URoTGkLugglo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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