SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7617a20d8c9682eb65722be38fe873869774252bc5dda5a484ac9dbd5033b9c8' 
  AND token = 'dGra8bq9GDzmuIjBsAVr69Aqmqxz8xUNvS2B5ytZjvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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