SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d67bed6d3a7fb01178ac4ac5113ba69cd0dc42465ccc0ffcace87b1b04c25a6' 
  AND token = 'JWmKZUwqEcOXPSsK0JY2a4c6SzuOwyhoRUmk0mjcAko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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