SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '555ace590afc16aab8c80e2fefcc1d18dbb719808422e83262c0ca239284eef0' 
  AND token = 'pqaoCvbCCtQOW4vCdRQXCbqPa00XAJOWEAgjvWJMuN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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