SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4987f09fa68b686658e265f3308b7d39a80d8a08912f34f59cb4143ec8950724' 
  AND token = 'bV2D+JvMckxuXINlqqpfKrZMxXRMpJjEvATaY/Jm3V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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