SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fe2e00c6a990e34695e3e5992bf117787405716556af833812deb64a31a31e7' 
  AND token = 'LjElV3F2ls2oEe99RLXuAXdWqeJFn9fSwlYtWSc8ECk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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