SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b82bb37dc8c45f1fa92f565a3afc09f3d390fb748084feba58b4322d7bda424' 
  AND token = 'wDQF568Lm3ySnKKJ0nMYDAFtqevYUpO4OKEPBPD6UqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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