SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ec86a843ad9e5aaba01db253f3a343a74d076d64eaddea134005ad3c60eb794' 
  AND token = 'i7deYuT5MczdLG0Jd10FpaNaImBMmOoiuzj5sVzaxSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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