SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c814f2433821298ba361bef5dc6257cefc78402b35b6ae9e8d6f4365a0bafc8' 
  AND token = 'unjHVVzxOsJRhJMGE0KcTsALGcJsl1XYBTv5SKb4eGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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