SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91957f5f3397966bebafe8f9fed05c4601cf524c87a484e0247600fb163a1433' 
  AND token = 'EKaw/9GkAIB05IFun7mY9xPzsk1RpVQsNU4Vht1Xqq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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