SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0670e33a14169af7f5954833938faa29fa73b7eb35e1f0569b7d84477c92e2de' 
  AND token = 'wcRqNWKuAvWvAkzIu2cGBiFzgequD2XnX4IhIVoop7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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