SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b03741f1abad04941ccab62a225d5243980b80d9b36df48adfebd4312306634' 
  AND token = 'NmRqxc57ehUi9rZWooNQ/2dmfpU/tDI5gLlBGpoL8mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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