SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e11d0375e7e54843443cec130acd09464b9f86f998576b6e90e95683e3fd535f' 
  AND token = 'vierWMwzx/DupvDPJ1GhHmrTSQs+mexGMm3OdpLL84U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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