SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e36f551bb6bac3a1c2693ccaca5b51dcc249d90161c93f4a1e17890252c61b20' 
  AND token = 'ECPnA3pgbgtmtd2UHWzlySDASyO2bREqo904hF3dR+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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