SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ffd6db0a7b6f84b54f4bde7c927c90b2d386d01d74289b1a67f651f35ee771' 
  AND token = 'YBizZ7HvsZR7VWNFd5KzWFlZR2Qygv5h8RZ/kmP32ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}