SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '62b5d94ace32390dd615a88183bc31dbd8b3d48c7c074817fcc70899fb1b1b43' 
  AND token = 'IBfTvYlZcJ6+/39b7mDr/jctW+Vq+lzBakD/L3QGSlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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