SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dbcfef6a8683677aaf5bfc805efab93050c3f5681b7f8ec829de66ed18ea564' 
  AND token = 'zAZKmWlKRfSo3PzZgwjSphKv/3HURzfusn22RtyRDD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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