SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ecb14874f7023ff7372306ca9d6ee7069c4a6eb733f328b09291a3794db747d' 
  AND token = 'ULpxIVNshuMmJ5ng/14ijpRwKTFUyHd5T0liXeV3aEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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