SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '676d8256300c6b309465e732cc12e7e6062800475233f4bd64670693b96b1f72' 
  AND token = 'TB9KhnlKN47zOULtYJZBdvC2yT1pJ9fXCelVEp1OW3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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