SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4095a516d24e5173f4c5ee25d05f11dccc73871e46b078ca019d2da4e9dc443' 
  AND token = 'XVjkgZDovRlBVilUDyYGkGNhrJqzKkg+vPjDqFqGDdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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