SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c8e964c19d0dcfb4dd6146158257e31c13f4d8b722ba4fc0f6ce2eb707c9e9' 
  AND token = 'XqTVTZVttNq5X1UqdNoIfVHkHuarCABNOcfYI5AssCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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