SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dee1cedea3c05603fabfee8da05ccecb938c970a69fcd7ae3f246587d735a71f' 
  AND token = 'j4tGIqq4C+A9SIUCnpP+rYhTBVTQ44vBdHuyD/wyucY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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