SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '881c9a1ccc03a4d20b90039026eba1af1b027c05072dc92df835af804ae6df35' 
  AND token = 'gofI/wMQb/tZ66V7YRkgTY4fqFjdDg2xd4EMDeE7nBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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