SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b9b48057f9f238a66c00cd60356a7b7fc782760df6a93b8e32eb2fa2aaa1827' 
  AND token = 'NUDOQauptfTZRNvg6nZxRYGhxw+ktEvD3B3tBb0p138=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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