SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fa1d52919e81daa39b50d492efb2c807f15bafb8bf562a6cce8c913347fe111' 
  AND token = 'oJnJ5AWLTFroN9WWdfEIXidIW3d+XFteonYgzVMsffU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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