SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b04c1c3040f9726f165f860606059bb92849e8dedf69532aa447dce4bdcc22f3' 
  AND token = 'KHvwadgfH+IRMlwOezDoOQayP5QYY+PmDv7rkhzPUhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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