SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '566407ad0cdb581208e72dfb116684b4d5f86555339f7f9d570c0543a900a74e' 
  AND token = 'm1qEq/TgTr7TGGXvp7SjEZT+VQlVkrOwq4fpsK4g13I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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