SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1617df4eaed7ecdc6c90204440f6abc7fb9b78835a6231c3dbf4053340087171' 
  AND token = 'hctPz3kgObpV72LWouwInXGZKqlx+tmwEiUSiWr4RDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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