SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89146080fc876b8925bc8e6ccb0616e865c99354d84ed539fcfb5d3532bc1d05' 
  AND token = '1x7rlIcng/VkFKCV2kOj6EDCObMmlhnv5uGYERmclfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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