SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f9b242de243c13dd34f8b02548d7b745fdc482359a2383de5177725bc2cfc18' 
  AND token = 'QDkQAL5lsHGo6pvuliEWAytm+ZtN46Bw8hh7mCT/Bjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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