SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b1f345fae85895c9b4cf98d148196f964f01d6b0eed27d30f6380ff45a51c24' 
  AND token = 'mCGhOx7VhNexa+ujb4HyRMdKQpvxSy6bDEX854tx2/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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