SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd69be31945549d0c2cb6f93152344801d18c6705ea065f861137bac5483ae723' 
  AND token = 'mv7nLqGFj7w+pOIIhjr4N4dHZ/787JOgqZmEj+flRv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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