SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39bc294798c2c9580967e5f15afd1cf66f9d1fd62c4dc7880218d233d475f048' 
  AND token = 'xg9woHJ9J9KiIyNpAzi2sPhkS0e3W80p5UKMBMa0+fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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