SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c83c0891bb79f00a9f25460c5ec93515c8adb24a0f49e3cc5271a6fdd570391' 
  AND token = 'hPuLlSCip5mVb+QiXPVFTjct4zx5soUXQ7jP3FxeVGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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