SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4ffbd7924ad9532129f8fcf383d9a4866a3c08763a6ca5bea92dfc19f2cc511' 
  AND token = 'vtzCcyFcxm9h8XatTfulQHUHRwcsUgM71fwDkDxADhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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