SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6699a2a5dbf6e39bc85c092918c268481eee1a0d36b7084e89b1e4527a2e7991' 
  AND token = 'YoLxTZdSOnJwiXYAwy1HbEP2tdgAUjL/+NwEYArLRLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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