SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '087dceac37f3d164b35afa1eb07e9602eb9e87f7a327037979fb0d82c73c35d7' 
  AND token = 'ykqnRx43dt19EHapWiJGXvGSplhLK10IrBD2+LeqXyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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