SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3967dad1e1e51b3a490d996507637e6ac8e10a13bd079750b1305cb92c378345' 
  AND token = 'b8XfxrpkcuQuISBIJPYTukgscLVORU2yYDSOgHG8szM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00095

JSON explain

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