SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a86e6bec5cff75da90486bbd8218aee9565a18d5fe16633f5263c4180fe7c77' 
  AND token = 'qiqa/FMq+/uQdpngC15w2wJYqIUv2nxnnruvj8H9hbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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