SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0661b4e54019879c113538cff6e1bd855a7a91f28ed6802ee542cabee87a3d49' 
  AND token = 'SHncFTU2vp7Lv+L+ieWRr7f4yKHnGQ3KFrq/7C9JcJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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