SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '851e16c5160922970430d00662fabca4d9c5e28a70c9859804b6fb02fef63668' 
  AND token = 'qP7GMFxMc+uQocaRZSc42vX4V2xJG2E5CP0tZZBYqgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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