SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d78cbd914fd9bba10773b4a30f435769bef1ff21161d4d6194b42660eba46e7' 
  AND token = '7ndwDYGlGVqupkL5FDkDKMnILCl1foHofE4Oj9hJEiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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