SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2443800bbee26d816b59dc16e6c3f5100fd0389f9b7518427f5fec0de0c054fa' 
  AND token = 'xIAkFTg2oNd3OCSmYnUymd5XxELiP/i/Ih4vloQegm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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