SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '496f0094594a06c12ac6646cc628740719daeb418123ea4caa56f953ab849f20' 
  AND token = 'Db5adYADUPk/jw+Ovufj/p2QmyBk/PDhqeL2RCAPYZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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