SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3584aa1568d06aed2bd76aa4927beafdd81fd69a09996e20b75d2b1eada1ed22' 
  AND token = 'pzDUO3/pdwT/3NDavVniFTHhczZmf3o5Jf/474+YZY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}