SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ace3e52e9686f1b13d60f04021d7660abae46cc1846a7c53341807e7395309c1' 
  AND token = 'Rb750uhzOegRCZYOYQUT4bS2X65dyeQlT3GleOk0B9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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