SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67c9528d1895ba3a1d0ac6d112cef4916f4b50d39713cd3f2287c6756e0fd94a' 
  AND token = 'MQvg8eGz5FZSh0o7grnbOVDLDunXom7CVmVpIaF1y9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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