SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0891001fdd28f3427acc4629a5ca32d5987c133aa419f2dde753d7f35924fb' 
  AND token = 'LZy4jaROtFUMfxmvitd84bYVEpBzG8/NIzXoNe/zVn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}