SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79dd410ffc6b2b32848c03f47d52f29636edd8010e75bbc57a29798c3d6a2d63' 
  AND token = 'W3cPUDOQhRig06wQ+amZ6PbjKWnptQIuhzHr354t1/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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