SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65878fc3a2e30299c370b3ec148781b715b331de60a395d2aa18d53becae3f3c' 
  AND token = 'qy53pmBsX2Y73b5wleLXkXm9PkqBndgFBl1Tf7jqUcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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