SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcfff6e3e0f82bee5e517597fd13f9da66faa697051110faaac7c6311be9e3e3' 
  AND token = 'TxibFoilmM4+ZIu1IIfpjX3K8RwcN4Uv5iwqbDtyDJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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