SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5c026f8ecbf8e934119068b778efcb7be337adf5eee622904ab9904c7c6a010' 
  AND token = 'W9GaZPsPloj3ZAMFbQJBNuYI0wKMvAHcJ2nFGmYgvkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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