SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c1de320ba3434fe9d613b4298b2b189779b5e37e8efd3c0a4dad5fc86b8506' 
  AND token = 'Y7xVnmJQs+Nm6TJiLferWCFTm/TS2KTBjqehNgPg2cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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