SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e217e12f627a0d350b74a05ad964934f0fb9016ca40b8005d3f52b9514adf71d' 
  AND token = 'LuS8dtvl3rFjU4C/35fIBWqCMuxw2663dMR8jRvGL8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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