SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f6f9d2018dcd15cacf3c4ed3966d10e7174c91463cc2beadccdb25a9237ab1b' 
  AND token = 'v7MToCIFT+FGf0jFRwhwKxGh6SOR/gbTuVhkQBpa6UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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