SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ee64e871d3c72955f30e03154a46f5301f3fd3c82309bf036550887a93d9073' 
  AND token = 'mcIWfDPTfMJC7kQq/qctSixauh10/tgoSFv77VptAaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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