SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f467f54d602a3c2bfa9e60699bc7c2f8035fd23e2e5cf87a8a42f90d0f2fdfc' 
  AND token = '5iSf2/E3kmQdRffKggqJQyQHxZf89egYtiNqZMcWYNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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