SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dad8102254d785c60132dd51afd3038c6461d292af4f8cb9e1d1b138df9f4904' 
  AND token = 'VkGoO20i6Lr/X8L+TUZ+oFcy4CPW5FJz/MwiIAvREAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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