SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a7d61e1be2612f86a4649d8c3250df44713e88fbc83408c7025d1e5b69ed693' 
  AND token = 'kjjLUXsZO5ZPU3JDtyw2GCyBqlSVf8hK6BCL5p3bZaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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