SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7204ae35d68c60df90fe45a0bc01e72f6a9b9f26684a88df4b82276228b53fb3' 
  AND token = 'xaPv7RbTtyQldiQYR9GBKC3ajF6qQgIXguAfkHBlzzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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