SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a614e0bbedc9ce763c301470c87d22dc8aae8e2adeee93cbc132d75a5dd0a92c' 
  AND token = 'MJnQryEniUxTxsxFe0xZJdISyIulPoQOVR3hRXoQImk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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