SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9454cdbe448366b072bb1f88cf0bd030bdd2c04b1c2901421ea3ace3e8f8ee38' 
  AND token = 'mF3tTDJYUTeQeZkRseWub1cgjQuR6XVnXtYMH235bi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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