SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deb0cb616ae5786fe94aca8b393a943b61c459d517557543a8411603eec48be8' 
  AND token = 'IzZq6xcuj2O7RLtsjWQRSIi810ICRvbALfSgj0V3J4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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