SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f618348cffc7732c45a903ac321eab9dc1fc0591db207659eaccee7b215342c' 
  AND token = 'CU3YZh+YtPi8h2zcDlqYHF+vLDQVeJ9edeAGG+SPQ+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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