SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9720f208e2ca8427682feb71d19b744265b5fdd2567e0390c107c1f13c511238' 
  AND token = 'VrgHF3PmdYFwS+ki2ujzAHS/CP3ehwtUHBz3IjEtLtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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