SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec46dfe6515079d7fa41e7cc1c1a05816781306bb81f26946d0ea185db23074b' 
  AND token = 'xRREVjX1On7q/o/N4HXJH69ctImtphKlYRSh+qW25Ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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