SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4efda2f3b963f88e20cde12b31791594260e7e51967cd5bc9a57cef588f49546' 
  AND token = 'YzQYNcYwusK2KiNYkXiPIx/vyNZtVSmtBh19PIlae9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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