SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5171dde89ac228a74611bf8bc414d6b3c72fc85bf9adb090f017ea95cc8721ac' 
  AND token = '9FkG0xS1GUowlLXUo3vrabO57LaqDZEgzHjY96G+dTE=' 
  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"
    }
  }
}