SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '835152cfe0cb1e60daa95d0138cec65e7acdc0c6078ed2543fe158ea06abf0ca' 
  AND token = 'gbC99jzHRgWQ/qcqZj9BLmYK+CS8aR6PZOLKyoaZpSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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