SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8caf4143f9b77eca64db7de95b08e8479973f6858a0e5fbee6a5c2c92247aff8' 
  AND token = 'qB7eT9Hu1kmDIrLYQ+O0vgjrBzubWpmFKq3pRX8BmYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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