SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28dab81d52cedb96f75d6f636a62df1f5fd646487abc6fdb402c024515b12d55' 
  AND token = 'lEroGKTjJLRvkzHrSViPuHTkUvH0vKboY+gXA5L9WzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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