SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85140e1dc1cd1a1d7c70abc11a8b7b2e560c80e242f806d7c0acb03db4442859' 
  AND token = 'To/vKzP9LVcPznBV/7CBxqvq0SiN1qDZtDqPrEaRc9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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