SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da0a4d77beec32cc66c5681df824698114f786fcf9ab75f7edfd9c31801374ca' 
  AND token = 'ATUwByheDIY6rp6mghULUy++HjxvlmS8n8xfDzJGyO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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