SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7557eafc036512130fad397ae43defada9c41fde475c2968ee2b26460d3c7b83' 
  AND token = 'O4K94LmfzqOLGMnmlZ+smJQcNqXJ4ngtbUXwxuRdlAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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