SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47f8697a244f3e7638554ff773758aa3a0015617f4fb76ec7dafb4e97f60212' 
  AND token = 'bhavnOx+NdhNmlKef97Xpv2eO1dNvpuers+rs8siFwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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