SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8d005dbf2d0676a64d819aeb41643e6e79fcf4181ee38a74619b60e99cadda2' 
  AND token = 'LNZJrdgSf2qttaU2pq63xlb54DiDk4AnZuCciULnG/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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