SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9d6cdbcba6aff3e4c526dedceea9f4b460a7fd65c87ea1581ac4b0934889209' 
  AND token = 'jTD2i5gGXPQcG6QVjKD8lR6ZUkTrwjOkpJWdKimq/8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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