SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542e71214ab240bca682ff8422d45f8ee1e23b3ea8627d579f8b6aafdf393ae0' 
  AND token = 'pgLG3z3SziwNQp6N3MKnbuFPkuKPuIlk8M/ty0XhJXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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