SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6e513f7d591e55b3d4cde71ddfc8559799cc293c278c78df783d15c6c247129' 
  AND token = 'QRTssH6wDRChWf0Pu8JE0wvm4nfhbJPDQKNwHQgDc8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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