SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad955630241de4d84aa9abb0709dd3549412c6b03c69b8d880e948a30d90a53b' 
  AND token = 'q4f2diCrwwN58XErHcQhevrF8zIveJ7PSvqnIKjtnIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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