SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d94e942df63b7e747dbae943448abe2e28672b97cbd6b47afd9b3578588419b' 
  AND token = 'v7CkiYDzLEYn37mxzpURnRlBvTscVU2aIa66hz8nSpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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