SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1417623baa9eea50245e2cf3fe4ca3498964103f690ca57a2502529ac50adb3a' 
  AND token = 'w69JOIk5SsMABxcTyrtBY3B9muQg7FpaUuncT9RAdv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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