SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa7300965ea0fa85f97d8cfebb3331052cf94dc4a1d5242f0fdeab5e064b1bfb' 
  AND token = 'bVJ9+UWAWo4iiGqQzNyHi/HjfDR/qdYKiiI/Lxq0KgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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