SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1704b7b16628a9e8b0fabd91658b78e46eab312d6ef9bd228f794edff5e2eb5' 
  AND token = 'zBmfSFlPCDTnQupbp1SUdpvGy644TfPhZbTmdmhVwLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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