SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ac5dfd714fa1a74da52f45081664fad06cc4b89d922b73774f2ab2f11d74873' 
  AND token = 'zU4AcHCz+mQnrBr7E66Kp5MqOJEIgWVZitKglVtn2uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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