SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11442b52695161951a43adf46bd56a91bca9f1e4a649d5f36104cce1d4370d48' 
  AND token = 'MKtUw7Y/v1UY/o8mP7wJfOPZ2ZiGDtQhwpQEjjU/0TY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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