SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2e2006a7550dd553384527fea0671592240a87d51c5a8fc1c1d241cefeb3dbc' 
  AND token = 'btthxH2Lec8tjkB2QuhnSYdsuFwxRTniVVlmpHUxGzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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