SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b369c4e23597009349db5ec9a12e64a22bb426c95b1fc1c677783a41feb1263f' 
  AND token = 'eRUiounc6GZzOE9VT6jfR9SEfnKkQ95DCzwJEyYAfUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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