SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee3abbb7459232a2d95b31eabd7bfb7e8f1d5602a6dca0b0a991d0c5327526c4' 
  AND token = 'eqvu20A+YWPL37GeU2kRttOfgMoGoslugMufMuXWNQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00007

JSON explain

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