SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66ec262245ef287469bf864b4e910bcf595eb0dceb7de1875a7c7905382fe334' 
  AND token = 'D2U1PLK8AH336MJ44vz91wpJhhMsqXpFENWv6pVvVlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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