SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc62c367105e55e1617487dd7c80d6dd4241ab4547bd63825048871c0c942da4' 
  AND token = 'Jq3iPdpsxP9d3hWVTTTrUZi0lR9WKlOqU4LsNtFxRv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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