SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18a65a97b7a165d60ec8392368158ae8fb7162b048d5c3a178d623370e6a2350' 
  AND token = 'iumP5nRrLeavsDcQ3X6LhmRTK6lZMKk6bK3v4TunOq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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