SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f40eb57cb48216a170f6238b3539b600ca96ccd65d59a988f2bdc179438e42a' 
  AND token = 'cVWKQf/VUTMlq8Kmr5i9Hn99eKQZGZ5Walqmfp9iATQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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