SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5094537916b1253cd5795f8f41faeb064a9c5d0e9a75748ea31fd27dc54ea9f8' 
  AND token = 'UIU0vMhHz1XFCYELeU+4N9ghRfXhzfwMBjuQK+yYfoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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