SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7bfd0a6cb5bc54bba4dc280db4dcdd9f1a6fd54e283e4b0e83618e8d90cbac0' 
  AND token = 'HmbvJNF5i5SekNw0AQbk3jkI8gCcbRiZQkMXCm1TgC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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