SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ffd4e5ec974ff117835bc00893608eb32bd167800e8c76f6cf011f98397fb78' 
  AND token = 'nGpqwSjOuWXZQTF6e54+4IwBxI/gZAjDeMoqrFzbkfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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