SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e4a7640fc60f8e7fd7b610485def651ce227e16939bc73fb231dc20ff5ea5d9' 
  AND token = 'MkFE6qIULtqHWpk0W70sIMuuxoSzLVvjCIhPaG5/Mps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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