SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fdb84c21e2c8fe927a87fdd82818f60ec3fa2626ed73bb4bf85534d80c72f78' 
  AND token = 'hWZIWOERM+77lXiN8MzJMcTxJ8IbxqwxmNzrgYNl/EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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