SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '917d2d2eb8e99c2991ab22d2e3180e59a742a651533b46f4c83d8c7205957766' 
  AND token = 'FX6EzBV+SXXE/jGcye9XOjvFLNo+wTw5fu+m4NqAB0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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