SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef70c53bd198b1d403dd402ec6b81b82210190abbc1b8adcc0325860ffec2792' 
  AND token = 'S0b2mVdTMjhP5D6/uoSeejif6FVVIL7TsLAHKcTKqcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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