SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55d07de626f928c0ff192d5af7ebdac2271cbeb81a22e81e81d67e497075dabc' 
  AND token = 'Zq3oCqETZDPXgXKLKDuEOdEHsearU3kRdET3MRx8/q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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