SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34e7dcb30d666577c4c207bf56fa2ce0b4483ace99c81120f52dc3a74be94440' 
  AND token = '//YqTNZHeLguiCbL/BVsv1Ou/1WXPWu/DovauCbQck4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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