SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5775dc532b563aa805d4c7dbb8b97eca6fab6100a2be0726fe00e863693ed62f' 
  AND token = 'vPVVAKPd3YyP+UMsD4gMD/Blwmt9lTu/BmeZ/xUJmlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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