SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '037b100fb191252f3fac2dd84dc073e1d5895e577ab6eb909018799c0ba07498' 
  AND token = '54eD65TgYZVLrSMyA7vWQ9qdy+UWrVxGPjZQTlV4y7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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