SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a587f50fc8610f95c3ad9414ff1e85b8809eb2d4ebf60ec796183a2b272f77fb' 
  AND token = 'KwFnmhWzwLyIc49W80mmiPsVb/0dgNNdVNg/PSM57PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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