SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ce314f42a719073408722d149abbdd0707235ab03013bbaa4ad2ec6f85b18bb' 
  AND token = 'iYgeCd1EXPY422uDy1Cnu6ZXEWAEh+SIT1QQnIJ/Chs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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