SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b9986daea0e732bb4985474df26c2963703b43a53e20aab3477e31b6d41610' 
  AND token = '8dTUhPGP1NID5r36WBaK6GknXBBw96FCFx3du0LERco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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