SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ed406fe3c6dd8584063ed04f79407f7af1613e93a2a351a60c30c175da63aa3' 
  AND token = 'iYtZCJTiOcgL4glzhkiSZT8NxayoGsDjk/+1h/N6hTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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