SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ea241c6f06250911b2efdf31aa8dad1af5b9193dec8d69d250a57de3057bba' 
  AND token = '1wxlZPDjmAuSbTGQa5nz0uBir20SjQw14TOdiU7XM7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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