SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa7c8b045c183ff53a92cf2e9afb26aa49693678af65ffbc92aa0799d646b690' 
  AND token = 'N7tjtLNuJBYMOW4WvrB8HnFOoX4yHGvWOZGJTKrMC8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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