SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9471fcfdecb59d380b7f78ebe1ad6f0b0408f9d680b783b86446cc0aa8bc9a1b' 
  AND token = 'KwdNqYhoORlJovahpns+2CiVfTBMk0+A9+svi44mDZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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