SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec3022a9aaf78ceda04cf54628f0aac23586cb29f133d9ef1954b88afb8a0688' 
  AND token = 'OGyA+AJYHqpYQd3hzXiOeYGYloAVDTzUviNym4CGnPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00138

JSON explain

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