SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfc60f12b079abc6137354d7c2b6d92c52a871298f5fadc66ced5372de989390' 
  AND token = 'LyG4MevUg4aP5+GzcV7VjQqNTvP1F/99VMH93W7qSiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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