SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b8860514f72c8a652fde7a180bf6dd8e032a71bd8267c441925c351154e1c13' 
  AND token = 'KvX3+X1XVK6CDMPnnEoEvSKn7+mEnl3ix9TGhOIliPs=' 
  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"
    }
  }
}