SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7573ac2249f24887093a8acd20c44a3eaf9500d19ff0ee7bb0c27a568f2101a8' 
  AND token = 'Y6+ivr8ZAGbdZOoSIpmyHwU4LN5lYIDcDwHQnXlDPqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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