SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0aa45b36c16a9fb47151032d97a494413d4eb414ac62a9741d2329af763ce99' 
  AND token = 'll9e+zLWxgpXQp2ZFxzJuuzUM+qyXwcsWJZOsc3RPqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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