SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86e4985bb0e97c50dbafec15a6541937b64087389ebf572c79aa8c1d98c90706' 
  AND token = 'MaVd9RI3gE8hIDurU+kbycW8KAonpomrojYKTXm0QQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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