SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98a89a9347b1cc2b22f9495163cd8dd8df5024cef35ca0a0303ff7de04e11357' 
  AND token = 'UJPtvCemFCf+YaSYKTfbCEqyZCTOJWx0yGa+p/6nBO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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