SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b0ed009e50c273e9224f7cdd90f378c25fb73f29eb58c8a156181eefc999f8a' 
  AND token = 'afXfRR53J5UqOjg3/gq17vFs+kqEOnVRAAnb4Iqo4qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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