SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85365c8655f5169a5a0c2fe77e9b7d99297b7dff1c46e979c12bab5e7432e79d' 
  AND token = 'NPjyZxw5v/u77rXdn4ZowwEhYFkYZ+ox+IHz7tPGtv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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