SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e1e1ee3629054bf61e3a26e4975075519cb8d84634bb7bc475ee2715cda1b4d' 
  AND token = 'ne/HuhnlKrQ589M+ILYZoCRn8WAqnVCXKZRmzwWRhiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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