SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bea81f60e00062c5fe73d0647956bcf4f7a43242b413f9d497ae0ebedb032c45' 
  AND token = 'Z/ZHzHTnxoobSHBdqGc8resyVCuIllcu4zmaRMhDYU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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