SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '974f8412204bd2b53800ad556298bcbdad02b6914016dc0504625d3efb3e0029' 
  AND token = 'th1/USGxzh4pZ64u/zCLbjWVfGxQkDBbi0iq2MTOWag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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